I had the same issue when adding a WidgetExtension to my functioning SwiftUI app. Was the same name in "Product Module Name" for App and Widget. This solved it for me.

Hi Ziqiao Chen, Do you know what the current state of my request is (FB16432110)? Is there any way to boost it? Kind regards, Jürgen

Thx a lot. I created FB16432110 (Access to location of indoor workout) and I‘m hoping for the API being available to all devs soon.